Spatial Properties of Cutaneous Temperature Sensitivity

描述（由申请人提供）：该项目的长期目标是了解热刺激如何在皮肤的感觉系统内部和之间整合。拟议的研究将测试三项新发现的假设，这些发现对当前的热接受理论提出了疑问：首先，皮肤冷纤维，其中许多也在高温下“矛盾地”放电，可能在热纤维也受到刺激时产生热的感觉；其次，在静态而非动态接触冷却过程中，在31 -25摄氏度之间的温和冷却可以产生刺痛和/或灼烧的伤害感（“无伤大患-冷伤害感”）；第三，很大一部分的冷热感觉可以通过更大的刺激接触皮肤最敏感部位的可能性来解释。提出了利用专门设计的热刺激器进行实验的建议：(1)验证热栅错觉（合成热）发生的假设，因为当热纤维也受到刺激时，冷刺激被编码为热，甚至热痛；(2)利用线性热模阵列研究合成热和悖论热，确定冷暖相互作用的时空特性；(3)验证“无害-冷伤害感觉”被动态接触皮肤产生的触觉刺激所抑制的假设，并探讨其与合成热和矛盾热相关的伤害感觉的关系；(4)使用一种独特的手掌热刺激器对空间求和的“敏感部位”解释进行进一步测试，这将使在模拟温度触觉探索的条件下研究整个手部的热感知和整合成为可能。除了增加我们对正常的温度敏感性如何依赖于温度、触觉和疼痛感觉之间的相互作用的知识外，所提出的研究结果可能有助于解释由温度触发的神经性疼痛，如冷感觉障碍和痛觉过敏，是如何由一个或多个皮肤感觉的传入处理中断引起的。

DESCRIPTION (provided by applicant): The long-term goal of this project is to understand how thermal stimulation is integrated within and among the sensory systems of the skin. The proposed research will test hypotheses stemming from three new findings during the present funding period that raise questions about current theories of thermoreception: First, that cutaneous cold fibers, many of which also discharge 'paradoxically' at high temperatures, may contribute to sensations of heat whenever warm fibers are also stimulated; second, that mild cooling between 31degrees -25 degrees C can produce nociceptive sensations of stinging and/or burning ('innocuous-cold nociception') during static, but not dynamic, contact cooling; and third, that much of summation of warmth and cold can be accounted for by the higher probability that larger stimuli will contact the most sensitive sites in the skin. Experiments are proposed that will take advantage of specially designed thermal stimulators to (1) test the hypothesis that the Heat Grill Illusion (Synthetic Heat) occurs because cool stimulation is encoded as heat, and even heat pain, when warm fibers are also stimulated; (2) determine the spatiotemporal properties of these warm-cold interactions via studies of Synthetic Heat and Paradoxical Heat using a linear thermode array; (3) test the hypothesis that 'innocuous-cold nociception' is suppressed by tactile stimulation produced by dynamic contact with the skin, and investigate its relationship to the nociceptive sensations associated with Synthetic Heat and Paradoxical Heat; and (4) provide further tests of the 'sensitive-site' explanation of spatial summation using a unique, handgrip thermal stimulator that will enable studies of thermal perception and integration throughout the hand under conditions that mimic haptic exploration of temperature. In addition to increasing our knowledge of how normal temperature sensitivity depends upon interactions among the senses of temperature, touch, and pain, the results of the proposed studies may help to explain how neuropathic pains that are triggered by temperature, such as cold dysesthesias and hyperalgesias, can arise from disruption of afferent processing in one or more of the cutaneous senses.